TY - JOUR
T1 - Protective nanometer films for reliable Cu-Cu connections
AU - Berthold, Tobias
AU - Benstetter, Guenther
AU - Frammelsberger, Werner
AU - Bogner, Manuel
AU - Rodríguez, Rosana
AU - Nafría, Montserrat
PY - 2017/9/1
Y1 - 2017/9/1
N2 - © 2017 Elsevier Ltd In this work, we report on the protective effect of platinum and carbon based films deposited onto Cu surfaces subject to pre-bonding temperature stress. The protection of Cu surfaces is an important and advantageous procedure to improve the reliability of Cu-Cu connections. The results were obtained from combined non-destructive Scanning Electron Microscopy (SEM) techniques and PeakForce Kelvin Probe Force Microscopy (PF-KPFM). As an indicator of degradation, the oxidation of the Cu surface was used. It could be shown that a C layer provides a much better protective effect than a Pt layer. Besides very local sporadically distributed Cu oxide grains, a gradual degradation of the protective carbon film was not even observable at the nanoscale for a stress temperature of 200 °C and layer thicknesses down to 3 nm. In contrast, with a 10 nm thick Pt film the Cu surface exhibits already at a stress temperature of 150 °C locally grown Cu oxide grains. The introduced carbon coating passivation of Cu surfaces has the potential of being a key technique for a reliable Cu-Cu wire bonding.
AB - © 2017 Elsevier Ltd In this work, we report on the protective effect of platinum and carbon based films deposited onto Cu surfaces subject to pre-bonding temperature stress. The protection of Cu surfaces is an important and advantageous procedure to improve the reliability of Cu-Cu connections. The results were obtained from combined non-destructive Scanning Electron Microscopy (SEM) techniques and PeakForce Kelvin Probe Force Microscopy (PF-KPFM). As an indicator of degradation, the oxidation of the Cu surface was used. It could be shown that a C layer provides a much better protective effect than a Pt layer. Besides very local sporadically distributed Cu oxide grains, a gradual degradation of the protective carbon film was not even observable at the nanoscale for a stress temperature of 200 °C and layer thicknesses down to 3 nm. In contrast, with a 10 nm thick Pt film the Cu surface exhibits already at a stress temperature of 150 °C locally grown Cu oxide grains. The introduced carbon coating passivation of Cu surfaces has the potential of being a key technique for a reliable Cu-Cu wire bonding.
KW - Copper protection
KW - Ion beam sputtering deposition
KW - PeakForce Kelvin probe force microscopy
KW - Protective nanometer films
KW - Scanning electron microscopy
U2 - 10.1016/j.microrel.2017.07.001
DO - 10.1016/j.microrel.2017.07.001
M3 - Article
SN - 0026-2714
VL - 76-77
SP - 383
EP - 389
JO - Microelectronics Reliability
JF - Microelectronics Reliability
ER -